Spark-plug



n. M. PRETTYMAN ANDIG. H. BROWN.

SPARK PLUG.

APPLICATION FILED MAR I. I919.

1,332,064. I Patented Feb. 24, 1920.

mmumum I Q, 0M, avwantoz flJZ/ re ma .UNITED PATENT OFFICE.

DANIEL M. PRETTYMAN AND GEORGE H. BROWN OF PORTLAND, OREGON.

SPARK-PLUG.

Specification of Letters Patent.

Patented Feb. 24, 1920.

Application filed March 1, 1919. Serial No. 279,970.

To all whom it may concern; 7

Be it known that we, DANIEL M. PRETTY MAN and GEORGE H. BROWN, citizens of the United States, residing at Portland, in the county of Multnomah, State of Oregon, have invented a new and useful S ark-Plug, of which the following is a speci cation.

This invention relates to improvements in spark plugs for internal combustion engines, the object of the invention being to provide a spark plug so constructed that it can be readily and thoroughly cleaned without removal thereof from the cylinder head and in which compression and fire from the cylinder are caused to pass through the plug for cleaning the same. 1 j I A further object of the invention is to provide a plug of the character described n which an unobstructed passageway is formed for the passage of compresslon and fire from the cylinder and in which manual means is provided for closing said passageway after the plug has been cleaned.

In the drawings accompanying and forming part of, this specification,

Figure 1 is a vertical sectional view showing our improved spark plug mounted in the cylinder head of an internal combustion enine' g Fig. 2 is a cross section taken on the line 2-2 of Fig. 1, looking in the direction of the arrows and showing the shell as provided with four ports or passages; and

Fig. 3 is a side elevation of the shell of the plug, showing a modified arrangement of the vent nut.-

The same characters of reference des1gnate the same parts in all the figures of the drawings.

In the embodiment herein illustrated, 2 designates the tubular shell of an ordinary form of spark plug provided with a core 3, which is usually formed of porcelain or other insulating material, said core being secured in the shell b means of a screw-threaded bushing 4:. entrally located within the core is an electrode 5 which projects beyond the lower end of the core and is connected at its upper end with a binding post 6 adapted to receive the terminal of a conductor. The other electrode 7 is secured to the shell at the lower end thereof in any suitable manner and projects toward the electrode 5, a small gap being left between the two electrodes for the production of the spark. The

shell is exteriorly threaded, as at 8, for engagement with the threaded spark-plug opening in the cylinder head, designated 9. The parts so far described are well known and in common use, and we therefore make no claim to these arts.

A constant source of annoyance to automobile users is the fact that oil and carbon frequently collect upon the porcelain core and the inner wall of the shell. This collection of oil and carbon fouls the plug and prevents the pro er firing thereof, and until such oil and car on are removed the spark plug is useless. Another of the chief causes of spark plug trouble, although perhaps not so generally understood, is dampness, which is one of the most frequent causes of short circuiting and damage to the plug beyond repair.

The present improvement is designed to produce a spark plug which not only can v be easily and quickly cleaned without removal of the same from the cylinder head, but in which the cleaning will also remove all dampness from the plug.

In the embodiment herein shown, the shell 2 is provided near its upper end with an externally threaded portion 10 which is adapted to receive an internally threaded nut 13, herein termed the vent nut. A number of vent openings 14; are formed through the shell within the threaded area 10 thereof, the vent nut being adapted to close such openings when screwed into place. The shell may be formed with a shoulder 15 at its extreme upper end, as shown in Fig. 1, in which case the vent nut is located below such shoulder and is adapted to be screwed upwardly so as to cooperate with said shoulder to form a gas-tight joint to prevent the escape of compression. In the form shown in Fig. 3 the respective locations of the shoulder and vent nut are reversed, this arrangement being preferable in some cases. In either case, however, the action of these two members is identical. In order that the abutting surfaces of the vent nut and shoulder may always be smooth so as to at all times form a perfect joint, we prefer to form a rabbet around the edges of these members where they come together, as shown at 16, so that when the shoulder and vent nut are in juxtaposition a groove is formed at this point, the purpose of which is to prevent accidental marring or burring of the shoulder or vent nut when a wrench is used, which burring would of course prevent the formation of a perfect joint.

When it is desired to clean the plug, all that is necessary is to loosen the vent nut approximately one half turn by means of a wrench while the engine is kept running. This opens the passageways through the shell and permits the compression and fire to escape from the combustion chamber through the plug, whereby all carbon, oil and dampness which may have accumulated on the walls of the plug as well as on.the core are burned off and discharged. The vent nut is then closed, the gas-tight joint preventing any compression from escaping from the engine in the ordinary running thereof.

"It will thus be seen that We have provided a plug which'can be cleaned without removal from the cylinder head and in which, by means of the unobstructed passage therethrough of the compression and firefrom the combustion chamber, all dampness and non-combustible oils are burned ofi and discharged, whereby the plug is left completely dry. One of the advantages of our improved plugiis that there are no movable parts such as coil springs or automatic valves to become fouled or clogged or otherwise to get out of order. A further advantage is that our improved cleaner shell can be applied to many of the plugs now on the market without altering the general form of the plugs.

WVe claim as our invention:

A spark plug comprising a core a shell adapted to receive said core and to be secured in the cylinder head of an internal combustion engine, a. shoulder on saidshell, a threaded portion contiguous to said shoulder, said shell being provided with a plurality of passageways passing through said threadedportion, and a nut on said threaded portion adapted to close said passageways, said nut and shoulder being so formed asto prevent marring of the contiguous edges thereof.

In testimony that we claim the foregoing as our own, we have hereto affixed our signatures in the presence of two witnesses.

DANIEL M. PRETTYMAN. GEORGE H. BROWN. Witnesses:

T. R. -MAT T,HEWs, 

